Britain's biggest mobile phone operator, Everything Everywhere, has been given up to a year’s head start in the race to launch 4G services and the chance to make a major grab for new customers.

Telecoms regulator Ofcom agreed to relax the rules around the use of Everything Everywhere’s spectrum – the airwaves that carry mobile signals – so that the company can plough ahead and launch a 4G, or fourth generation, mobile network this year.

The 4G service will allow customers of the Orange and T-Mobile networks that Everything Everywhere operates much speedier access to the internet over mobile phones.

Typically, users will be able to download information 10 times faster than they are able to over existing 3G networks, and they will eventually be able to download content three times faster than is currently possible on the fastest fixed-line broadband network.

But Ofcom’s decision will hand Everything Everywhere a major competitive advantage over rivals. It will also boost Three, the smallest of the “Big Four” mobile operators, which yesterday struck a deal to buy a large portion of the Everything Everywhere spectrum that can now be adapted for 4G services.

However, rivals Vodafone and O2 will not be in a position to launch competing 4G networks until well into next year. They are waiting for Ofcom’s long-awaited auction of 4G spectrum before they build their own networks, and could end up lagging behind Everything Everywhere by up to 12 months.

Stuart Orr, a telecoms expert at consultancy firm Accenture, said Ofcom’s ruling handed Everything Everywhere a “springboard” for winning new customers and marked “a hugely important evolution for UK operators competing to own coverage”.

Kester Mann, an analyst at CCS Insight, said: “It gives Everything Everywhere a big head start. It enables it to promote its services as the fastest and the highest quality in Britain, which Vodafone and O2 won’t have a chance of doing for quite some time.”

Vodafone reacted angrily to Ofcom’s ruling. It said it was “frankly shocked” by Ofcom’s decision and accused the regulator of a “careless disregard for the best interests of consumers, business and the wider economy”.

The regulator has refused to properly take account of the “competitive distortion” that its ruling will create, Vodafone said. Everything Everywhere claims that allowing it to get a head start on 4G roll-out would be good for Britain’s economy, and help the UK to catch up with America and large swathes of Europe which already have 4G networks.

Mr Mann said Ofcom’s “brave” decision was likely to spark a “strong backlash” but that it would help the UK which has “lagged its European counterparts on this for too long”.

However, the mobile operator’s rivals argue the head start will actually damage the economy in the long term by creating an uneven playing field and stifling competition between mobile operators.

O2 was also angry at Ofcom’s ruling, saying: “We are hugely disappointed with today’s announcement, which will mean the majority of consumers will be excluded from the first wave of digital services. This decision undermines the competitive environment for 4G in the UK.”